When I look at all the pictures on the backscatter website I see what looks like the same interface as my epl2 housing.

The standard port looks different, but the port looks removable. If you look at the pic looking into the housing with the door open, you can see the locking tab on the port. At least, that's what I think I see.

Also look at the picture from straight above. You clearly see a gap between the housing and the port.

Ok guys, the original poster specifically asked about the 8mm FE on a PEN housing with precision dome.

Now, let's compare the size weight of a PEN housing with the precision dome and what ever RX100 housing you chose with the necessary add on lens to get you to equivalent FE view. I don't have those numbers, but based on my experience with the Inon 165AD I'd be willing to bet there's barely a scintilla of difference in size & weight.

And what about the optical performance of the compact camera lens and then going through a flat port, then an add on lens.

As opposed to a dedicated FE lens and port. That's what he asked about.

I gave my EXPERIENCE with the ZEN semi dome which works well for some of other lens.

It would be nice if someone gave actual experience of the precision dome with the 8mm on the PEN housing.

Interceptor in your list of weights, what is the weight with an add on FE lens?

did you see the link john referenced with the photo by Alex Mustard with the em5 & 8mm FE?

Can you show anything equivalent from an rx100.

As far as the size issue. I had an inon 165AD FE lens on a Fuji F30 about 5 years ago. I replaced it with the epl2.

That little tiny F30 with the add on lens was essentially the same size as my epl2 with the Zen 100 port, but the F30 had worse handling characteristics because all the weight was in the front. And an Oly PEN housing with the precision port is even a smaller profile.

So, for shooting FE, it's my opinion that the PEN with precision dome will be a better handling rig than an add on wet mount FE lens.

Understand, I'm not bashing the rx100 and if I was buying from scratch today it would be high on my list.

I just find some of these statements and claims hard to believe. And most come with no proof.